 |
| Titel |
Dayside aurorae and polar arcs under south-east IMF orientation |
| VerfasserIn |
P. E. Sandholt, M. Dyrland, C. J. Farrugia |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 24, no. 12 ; Nr. 24, no. 12 (2006-12-21), S.3421-3432 |
| Datensatznummer |
250015715
|
| Publikation (Nr.) |
 copernicus.org/angeo-24-3421-2006.pdf |
|
|
|
|
|
| Zusammenfassung |
| We document a characteristic spatial and temporal structure of the
aurora in the postnoon sector
present during a 10-h-long interval of very steady
southeast IMF orientation (clock angle=135°)
ending in a sharp south-to-north transition.
Focus is placed on the
detailed morphology of auroral forms/activities corresponding to
merging and lobe convection cells
obtained from SuperDARN convection data and
Greenland magnetograms.
The ground optical instruments at Ny Ålesund,
Svalbard (76° MLAT)
recorded different auroral forms/activities
as the station moved to higher magnetic local times (MLTs)
in the 13:00–17:00 MLT sector.
Whereas the 13:00–15:00 MLT sector is characterized by
classical poleward moving auroral forms (PMAFs)
associated with merging cell transients,
the aurora in the 15:00–17:00 MLT sector shows instead
a characteristic latitudinal bifurcation consisting of standard oval
forms and
polar arcs, and a corresponding
composite pattern of merging and lobe convection cells.
The merging and lobe cells
respond to the southward and northward IMF transitions
by activation/fading and fading/activation, respectively.
A sequence of brightening events is
characterized by successive activations
progressing in latitude from the merging cell regime to the
lobe cell regime.
Emphasis is placed on the association between polar arc brightenings
and the activation of the channel of
enhanced sunward flow in the lobe cell.
The observations are discussed
in relation to recent work on solar wind-magnetosphere-ionosphere
interconnection topology. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|